The following disclosure relates to a sheet tray configured to support and position a sheet and to an image forming apparatus including the sheet tray.
A sheet tray is conventionally mounted on an image forming apparatus such as a copier and a printer. The sheet tray supports a sheet to be supplied to an image forming device configured to form an image. Examples of the sheet tray include: a cassette tray accommodatable in the image forming apparatus; and a plate-like tray mounted on a side surface of the image forming apparatus so as to extend obliquely. The sheet tray is provided with at least one guide for positioning the sheet in accordance with the size of the sheet.
One example of the at least one guide is a pair of right and left side guides configured to determine the sheet in a widthwise direction. Common side guides are slid toward and away from each other by racks and a pinion gear. Thus, when one of the side guides is slid in one direction, the other side guide is slid in the other direction in conjunction with the movement of the one sheet guide. The one side guide has a protrusion at its lower portion. When the protrusion is engaged with one of grooves formed in the sheet tray, the one side guide is positioned.
To disengage the protrusion and the groove, the one side guide is provided with an operation portion shaped like a knob. A user slides the side guide while holding the operation portion. It is assumed that the operation portion is principally operated with a right hand, and the operation portion is usually provided on a right side guide viewed from the user operating the image forming apparatus, making it difficult for a left-handed user to operate the operation portion.
To solve this problem, in a conventional image forming apparatus, a lock member constituted by a protrusion and an operation portion formed integrally is detachably attached to one of right and left side guides, and this lock member is attachable to any of the side guides. Thus, a user can attach the lock member to a desired one of the side guides, depending upon his or her dominant hand.